Numerous changes
have been made to the KX250F. It produces significantly more power than
the 2005 model it replaces, and like the new flagship KX450F, the KX250F
sports an all-aluminum perimeter frame.
The 249cc,
liquid-cooled, four-stroke engine now gives the KX250F a harder-hitting
powerband, especially from mid- to high-rpm, and it extends that smooth,
traction-grabbing power into the over-rev range.
Additional
enhancements include revised intake and exhaust ports, and a revised
combustion chamber for stronger low- to mid-rpm performance, while new cam
profiles and a higher 13.5:1 compression ratio improve high-rpm
performance. To compensate for the increased output, the piston now has a
thicker crown.
Other engine
modifications include stiffer valve springs to help ensure reliable valve
control at high rpm; a surface-hardened crankshaft for additional
rigidity; more efficient oil pumps that increase oil flow by nearly 20
percent; a new stick ignition coil that reduces overall weight; and newly
designed, high-capacity Denso radiators that deliver superior cooling
performance due to their more tightly packed cores and new fin design.
Kawasaki also revised the timing and lift of the decompression system, so
starting the KX250F is even easier.
The clutch and
five-speed transmission have also been modified to include new friction
plate material and stiffer clutch springs for improved clutch feel, and
the gears have beefier dogs to match the more-powerful engine. Kawasaki
engineers have also given the KX250F shift drum a new cam to improve
shifting feel.
The most visible
change to the KX250F is the aluminum perimeter frame. As with the KX450F,
Kawasaki engineers combined their experience designing steel perimeter KX
frames and techniques used to construct the Ninja ZX-10R sport bike
chassis to create an all-new aluminum perimeter frame. Comprised of
forged, extruded and cast aluminum parts, the strong but light design
gives the KX250F the best possible balance of torsional and longitudinal
rigidity necessary for superior handling characteristics.
The frame was
designed so that the center of gravity and key chassis dimensions would
work together to enhance the rear tire's ability to drive the KX250F
forward instead of squatting under acceleration. Additionally, the
four-stroke engine sits in an upright position within the new frame to
further aid overall traction.
The slim profile of
the KX250F frame, two-piece radiator shrouds that leave the upper frame
spars exposed, and careful design of the remaining bodywork make the
KX250F feel light and narrow beneath the rider.
The KX250F's
high-performance suspension has been designed to complement the new frame.
Up front, a Showa twin-chamber fork keeps the oil and air in separate
chambers for consistent damping performance during long motos. On the
rear, a new UNI-TRAKĀ® rear suspension system, featuring an alloy swingarm
with tapered spars and revised linkage ratios maximizes traction under
acceleration.
Front and rear petal
disc brakes provide stopping power for the KX250F. This design not only
helps to reduce unsprung weight, but the petal shape of the discs helps to
clean the brake pads for more efficient braking performance.
In addition to
aggressive new bodywork and a new seat, the KX250F comes with a Renthal
aluminum handlebar and an aluminum skid plate as standard.
To minimize overall
weight, the KX250F utilizes aluminum instead of steel for several
components, including the clutch cable elbow, clutch cable fitting nuts,
fuel tank fitting nuts, seat mounting brackets, front brake hose clamp and
igniter stay bracket. Kawasaki engineers also eliminated the upper
mounting brackets of previous designs for the plastic fork protectors.
Optional parts for
the KX250F include magneto rotors with different inertias, a 12-tooth
countershaft sprocket, top mounting clamp for an oversized handlebar,
aluminum and steel rear sprockets, solid petal brake rotors for wet races,
different springs for the front fork and rear shock, manual decompression
lever and cable, and a 20-inch front wheel.
FEATURES
Engine
- 249cc, liquid-cooled, four-stroke engine delivers hard-hitting power
from mid-
to high-rpm
- Wide powerband extends smoothly into the over-rev
Top End
- Revised intake and exhaust ports, and revised combustion chamber improve
low-
to mid-range performance
- Rev-limiter settings and ignition timing have been revised to extend the
engine's
over-rev capability
- New cam profiles help increase high-rpm performance without sacrificing
low-end
performance
- Piston features a thicker crown to compensate for increased power and
higher
compression ratio
- Once-piece magneto rotor offers improved reliability
- New stick ignition coil saves weight and offers improved performance
Bottom End
- Crankshaft is surface-hardened for additional rigidity
- Countershaft sprocket has more - and smaller - splines to increase
reliability
- More efficient oil pumps increase oil flow by nearly 20 percent
Cooling
- Newly designed, high-capacity Denso radiators are slimmer
- Radiator features more tightly packed cores and a new fin design to
deliver superior
cooling efficiency
Shifting
- New friction plate material and stiffer clutch springs improve clutch
feel
- New clutch lever design compensates for higher spring rate
- Five-speed transmission dogs are beefier to match the engine's increased
power
- Shift drum features new cam for improved shifting feel
Frame
- All-aluminum perimeter frame features composite structure, utilizing
forged,
extruded and cast components
- The slim profile of the frame, two-piece radiator shrouds that leave the
upper frame
spars exposed, and careful design of the remaining bodywork
make the KX250F
feel light and narrow beneath the rider
Front Suspension
- Showa twin-chamber fork keeps oil and air in separate chambers for
stable damping
performance during long motos
Rear Suspension
- New UNI-TRAK rear suspension system features revised linkage ratios to
suit the
new fame and swingarm
- Alloy swingarm uses cast front section, tapered hydroformed spars and
forged chain
pullers; the tapered spars are shaped to match the balance of
flex and rigidity
required of the aluminum frame, and allow additional clearance
for the rear brake
caliper when the rear suspension is fully compressed
- Smaller rear chain guide reduces overall weight
Brakes
- Front and rear brakes utilize new petal discs, helping to reduce overall
weight
- Petal discs help to clean the brake pads for more efficient braking
performance
Wheels
- New rear wheel helps to reduce unsprung weight
From the Cockpit
- Renthal aluminum handlebar is strong and reduces overall weight
- Short-length grips feature a special pattern to reduce vibration
transmitted from the
bars to the rider
New Styling
- New bodywork and new seat have aggressive style
Options
- Different inertia magneto rotors
- 12-tooth countershaft sprocket
- Top handlebar clamp for an oversized bar
- Aluminum and steel rear sprockets with optional tooth sizes
- Solid petal brake rotors for wet racing conditions
- Optional springs for the front fork and rear shock
- Manual decompression lever and cable
- 20-inch front wheel
SPECIFICATIONS
Engine: Four-stroke single with DOHC and four valves
Displacement: 249cc
Bore x stroke: 77.0 x 53.6mm
Cooling: Liquid
Carburetion: Keihin FCR37 and hot start circuit
Compression ratio: 13.5:1
Ignition: Digital AC-CDI
Transmission: Five-speed with wet multi-disc manual clutch
Final drive: Chain
Frame: Aluminum perimeter
Rake / trail: 27.5 degrees / 4.7 in.
Front suspension / wheel travel: 47mm inverted twin-chamber telescopic
fork with 16-way compression and rebound damping / 12.4 in.
Rear suspension / wheel travel: UNI-TRAKĀ® linkage system with 13-way
low-speed and 2-turn high-speed compression damping, 17-way rebound
damping and fully adjustable spring preload / 12.2 in.
Front tire: 80/100-21 51M
Rear tire: 100/90-19 57M
Front brake: Single semi-floating 250mm disc with dual piston caliper
Rear brake: Single 240mm disc with single-piston caliper
Overall length: TBA
Overall width: TBA
Overall height: TBA
Ground clearance: TBA
Seat height: TBA
Dry weight: TBA
Wheelbase: TBA
Fuel capacity: TBA
Color: Kawasaki Lime Green / Black
MSRP: TBA
|